Collar bushing terminal



Jan. 8, 1963 R. L. NORRIS 3,072,881

COLLAR BUSHING TERMINAL Filed Aug. 20, 1959 2 Sheets-Sheet J.

7 INVENTOR. Roberi- L. Norms I0 I Jan. 8, 1963 R. L. NORRIS 3,072,881

COLLAR BUSHING TERMINAL F'iledAug. 20, 1959 2 Sheets-Sheet 2 I I Alkfila? INVENTOR.

Rober+ L. Norms BY y ATTORNEYS Patented Jan. 8, 1963 3,072,881 CQLLARBUSHING TERMINAL Robert L. Norris, Birmingham, Ala, assignor to AndersonElectric Corporation, Birmingham, Ala., a corporation of Alabama FiledAug. 20, 1959, Ser. No. $34,971 3 Claims. (Cl. 339-272) This inventionrelates in general to cable terminal connectors and more particularly tosolderless cable terminal connectors particularly adapted for use asterminal connectors on power transformers and the like.

Desirable features for a cable terminal connector include a singleadjusting device to clamp the cable securely in the cable terminalconnector, a deep continuous cable contact groove that can retain anoxide inhibitor, means for self compensation for creep or cold flow ofthe retained cable especially when said cable is aluminum, a captive yetremovable clamping device, a workable configuration that will attain theother ends herein yet is constructable in aluminum so as to avoidsurface problems when aluminum cable is connected, and a large cableaccommodation range.

Previous devices have fallen into three major categories comprising theeyebolt type terminal, the U-bolt or 2-bolt type terminal, and thestandard collar type terminal. Each of these approaches to the problemattains some, but not all, of the aforesaid desirable features. Allthree of the aforesaid approaches require an extrinsic cold how or creepcompensating device.

In addition the eyebolt type has a divided groove that cannot easilyretain an inhibitor and does not lend itself to fabrication in aluminum,this latter defect requiring for example a tin-plated bronze eyebolt foruse with aluminum cables, which is undesirable. In addition the dividedgroove of the eyebolt produces two high pressure contact areas whichenhance creep of conductors of aluminum, etc.

The U-bolt and 2-bolt types also have additional disadvantages, chiefamong these being that their cable accommodation range is small and theyentail the adjustment of two nuts when being employed.

The additional disadvantages of the standard collar type terminal areits shallow groove that cannot retain inhibitor, its small cableaccommodation range, and its non-captive non-positive pressure clampingdevice.

It is, therefore, an object of the present invention to provide a securemechanical and electrical connection between a cable terminal and acable that will remain secure even though the cable material may coldflow or otherwise change its radial dimensions.

Another object is to provide a single tightening means so as to permitrapid and easy connection and disconnection of the cable in theterminal.

An additional object is to provide a clamping configuration of extrudedaluminum so as to accommodate aluminum cables without the necessity ofusing a plated bronze fitting as required when non-aluminum clampingmembers are used.

A further object is to provide a deep continuous cable contact groovethat improves the mechanical and electrical connection and also providesgreatly increased retention of an oxide inhibitor.

A still further object is to provide a captive clamping means that canbe used with a wide range of cables.

Other objects and a fuller understanding of the invention may be had byreferring to the following description and claims, taken in conjunctionwith the accompanying drawings in which:

FIGURE 1 is an exploded perspective of a first embodiment of theinvention;

FIGURE 2 is a normal perspective of said first embodiment;

FIGURE 3 is an elevation of said first embodiment;

FIG. 4 is a bottom view of said first embodiment;

FIG. 5 is another elevation of said first embodiment;

FIG. 6 is an exploded perspective of a second embodiment of theinvention;

FIG. 7 is a normal perspective of said second embodiment;

FIG. 8 is an end elevation of said second embodiment; and

FIG. 9 is a side elevation of said second embodiment.

With reference to the drawings, and particularly FIGS. 1-5 inclusive,the present invention comprises, in general, a fixed base and bushingmember 16*, a detachable collar member 11 adapted to mate with base andbushing member 1%, and an operating bolt 12 disposed to thread throughsaid detachable collar member 11.

As illustrated, fixed base and bushing member 10 comprises base platemember 13 having tapped mounting hole means 14 therein, extension memberor body portion 15 extending normally from said base plate member 13,semi-cylindrical bushing member or stud 16 of channel or U-shapedcross-section extending at a right angle, or generally to the right asviewed in FIG. 1, from said extension member 15 with its opensemi-cylindrical inner face or groove 17 opening upwardly as viewed inFIG. 3, a semi-cylindrical indentation or groove 18 in said extensionmember ISbeing essentially a continuation of the groove 17 of saidbushing member 16, a pair of projections or cars 19 being disposedradially outward at the upper part of the outermost end 20 of bushingmember 16, and a fiat bearing surface 21 on the underside 22 of bushingmember 16 generally centrally thereof to accommodate bolt 12 ashereinafter described.

It is to be noted that all the above described structure appurtenant tobase and bushing member 10 may be constructed integrally therewith as bycasting, and preferably such casting should be of aluminum in order toobtain the benfits set forth in the objects herebefore recited in regardto the desirability of using aluminum jaws to grasp aluminum cables.

Also as illustrated, detachable collar member 11 comprises anopen-centered or hollow aluminum body member 23 whose upper portion 24as viewed in FIGS. 1-3 is shaped to form a pair of springing portions orshoulders 25, a movable clamp jaw '26 having an inner grooved face 27,and an oppositely disposed tapped adjusting boss 28 on the lower portion29 of said body member 23. I aw 26 defines a pair of recesses 25a on itsopposite sides which are adapted to receive respectively sides 16a ofthe channel-shaped stud 16. These recesses are substantiallycomplementarily shaped with respect to the stud sides so that they canaccommodate and substantially completely receive these stud sides when avery small size conductor is clamped between the inwardly projecting jaw26 and the groove of the stud 16'.

The inner (vertical as viewed in FIGS. 1, 2, 4 and 5) dimension ofcollar member 11 is slightly less than the outer vertical dimension ofstud 16 (measured between the undersurfaccs of the projections 19 andthe upper surface of body portion 15) with which it mates. Also (seeFIG. 3) the major transverse dimension of collar member 11, that is,from the inner surface 3% of base 28 to the face or groove 27 of clampjaw 26, is larger than the extreme transverse distance between theouter-most reach of cars 10 whilethe minor transverse inside dimensionof collar member 11 is a shade larger than the total lateral dimensionof semi-cylindrical bushing member 16 with which it mates.

In order to obtain the benefits set forth in the aforesaid objects, itis desirable that the collar member 11 be of aluminum, and furthermoreof extruded aluminum. Aluminum matching jaws of the bushing terminalassembly can deal most effectively and simply with aluminum aorassrcable, obviating the necessity of using plated bronze for said jaws,while extrusion of the collar member 11 presents hardened shoulders 25thereof which are capable of sufiicient resilience to accomplish thecreep compensating function hereinafter described.

The base and bushing member may be afiixed to, say a transformer frame,by bolting into the tapped hole 14. The inner face or groove 17 ofbushing member 16 may then be lined with an oxide inhibitor (not shown).The collar member 11 is then slipped over bushing member 16 bypresenting the major transverse inside dimension of collar member 11 tothe ears 19 on bushing member 16. A ninety degree turn of collar member11 will then engage ears 19 over the sides 31 of collar member 11situated the minimum transverse distance apart. A conventional conductoror cable 32 may then be inserted into the opening between the movablejaw face 27 and the inner fixed face 17 of bushing member 16.

Operating bolt 12 is then inserted by threading through boss 23 oncollar 11 until it contacts or bears against fiat bearing surface 21 onbushing 16. Further turning of bolt 12 will draw movable jaw 26 oncollar 11 toward fixed bushing 16. When cable 32 is contacted by bothmovable jaw face 27 and groove 18, further tightening of bolt 12 willresult in flexing of springing shoulders 25. When thus furthertightened, aluminum cable 32 receives spring loaded pressure that willcompensate for any relaxation or creep in radial dimension of the cableand thereby maintain the desired secure mechanical and electricalcontact between bushing assembly and cable.

It will be noted that when in this assembled and tigh ened position, thealuminum cable 32 is grasped in a non-hostile aluminum grip, renderedself-compensating by the aforesaid extruded aluminum spring action, andis capable of retaining any oxide inhibitor applied to said jaw faces18, 27. Furthermore, once the operating bolt 12 is tightened down to thedesired torque, the clamping collar 11 is captive with respect to thebushing 16, although the whole connection is rapidly removable byloosening the single operating bolt.

in addition the matching male and female contours of bushing member 16and shoulders 25 and jaw 26 of collar 11 respectively, permit a widedegree of approach and withdrawal of such members relative to oneanother thereby providing accommodation of a correspondingly wide rangeof cable sizes.

It will be observed that all the foregoing recitation of structure andfunction was directed to the first embodiment illustrated in FIGS. 1-5inclusive. The second embodiment shown in FIGS. 6-9 inclusive differsfrom the above not at all in general function, and difi'ers in actualstructure only in the orientation of its base plate member 13, saidmember 13 being oriented to allow a connected cable 32 to extend normalto the mounting surface rather than parallel to it. Said secondembodiment is merely a slight variation in application from said firstembodiment, and may be practiced with the same structure and operationas hereinbefore disclosed.

Although this invention has been described with a certain degree ofparticularly, it is understood that the present disclosure has been madeonly by way of example and that numerous changes in the details ofconstruction and the combination and arrangement of parts may beresorted to without departing from the spirit and the scope of theinvention as hereinafter claimed.

What is claimed is:

l. A terminal connector for electrical power cables comprising a bodyportion, a stud thereof of channelshaped cross section, a collar havingan opening accepting said stud and having a jaw which projects inwardlytoward the groove defined by said channel section and is adapted forreception therein, said jaw defining recesses on opposite sides thereofadapted to receive the sides of the channel-shaped stud, meansassociated with said collar for forcingsaid jaw into clamping engagementwith an electrical conductor inserted into said groove, said recessesbeing substantially complementarily shaped with respect to said studsides and adapted to receive said sides whereby a wide range ofconductor sizes may be clamped, said collar having portions adjacent therecesses on opposite sides of said jaw which are adapted resiliently toflex under clamping pressure thereby to provide a spring bias formaintaining clamping pressure upon relaxation of said conductor, andmeans adapted to hold the collar captive axially on said stud.

2. A terminal connector as set forth in claim 1 in which said meansincludes projections at the end of said stud, said collar being heldcaptive axially on said stud by said projections with said jaw oppositethe groove defined by said channel section.

3. A terminal connector as set forth in claim 1 in which said meansincludes ears at the end of the stud, and the minimum lateral dimensionsof the interior opening of said collar are greater than the maximumlateral dimensions of said stud whereby said collar is adapted to beheld captive axially on said stud by said ears with said jaw oppositethe groove defined by said channel section and adapted to be removabletherefrom when rotated approximately relative to said stud about thelongitudinal axis thereof.

References Cited in the file of this patent UNITED STATES PATENTS1,991,075 Bloomquist Feb. 12, 1935 2,068,152 Rowe Jan. 19, 19372,809,363 Schertel et al. Oct. 8, 1957 FOREIGN PATENTS 497,089 CanadaOct. 20, 1953 226,097 Switzerland June 16, 1943 233,001 SwitzerlandSept. 16, 1944

1. A TERMINAL CONNECTOR FOR ELECTRICAL POWER CABLES COMPRISING A BODYPORTION, A STUD THEREOF OF CHANNELSHAPED CROSS SECTION, A COLLAR HAVINGAN OPENING ACCEPTING SAID STUD AND HAVING A JAW WHICH PROJECTS INWARDLYTOWARD THE GROOVE DEFINED BY SAID CHANNEL SECTION AND IS ADAPTED FORRECEPTION THEREIN, SAID JAW DEFINING RECESSES ON OPPOSITE SIDES THEREOFADAPTED TO RECEIVE THE SIDES OF THE CHANNEL-SHAPED STUD, MEANSASSOCIATED WITH SAID COLLAR FOR FORCING SAID JAW INTO CLAMPINGENGAGEMENT WITH AN ELECTRICAL CONDUCTOR INSERTED INTO SAID GROOVE, SAIDRECESSES BEING SUBSTANTIALLY COMPLEMENTARILY SHAPED WITH RESPECT TO SAIDSTUD SIDES AND ADAPTED TO RECEIVE SAID SIDES WHEREBY A WIDE RANGE OFCONDUCTOR SIZES MAY BE CLAMPED, SAID COLLAR HAVING PORTIONS ADJACENT THERECESSES ON OPPOSITE SIDES OF SAID JAW WHICH ARE ADAPTED RESILIENTLY TOFLEX UNDER CLAMPING PRESSURE THEREBY TO PROVIDE A SPRING BIAS FORMAINTAINING CLAMPING PRESSURE UPON RELAXATION OF SAID CONDUCTOR, ANDMEANS ADAPTED TO HOLD THE COLLAR CAPTIVE AXIALLY ON SAID STUD.